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Related papers: Temperature dependence of the contact in a unitary…

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Thermodynamic properties of an ultracold Fermi gas in a harmonic trap are calculated within a local density approximation, using a conserving many-body formalism for the BCS to BEC crossover problem, which has been developed by Haussmann et…

Statistical Mechanics · Physics 2009-11-13 R. Haussmann , W. Zwerger

The temperature dependence of the conductance of a quantum point contact has been measured. The conductance as a function of the Fermi energy shows temperature-independent fixed points, located at roughly multiple integers of $e^{2}/h$.…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 V. Senz , T. Heinzel , T. Ihn , S. Lindemann , R. Held , K. Ensslin , W. Wegscheider , M. Bichler

The entropy and kinetic, potential, and interaction energies of an atomic Fermi gas in a trap are studied under the assumption of thermal equilibrium for finite temperature. A Feshbach resonance can cause the fermions to pair into diatomic…

Statistical Mechanics · Physics 2009-11-10 L. D. Carr , R. Chiaramonte , M. J. Holland

Atomic Fermi gases provide an ideal platform for studying the pairing and superfluid physics, using a Feshbach resonance between closed channel molecular states and open channel scattering states. Of particular interest is the strongly…

The universal Tan relations connect a variety of microscopic features of many-body quantum systems with two-body contact interactions to a single quantity, called the contact. The latter has become pivotal in the description of quantum…

Strongly interacting, dilute Fermi gases exhibit a scale-invariant, universal thermodynamic behaviour. This is notoriously difficult to understand theoretically because of the absence of a small interaction parameter. Here we present a…

Quantum Gases · Physics 2010-08-25 Hui Hu , Xia-Ji Liu , Peter D. Drummond

We calculate and measure the density distribution and cloud size of a trapped two-dimensional $^{6}$Li Fermi gas near a Feshbach resonance at low temperatures. Density distributions and cloud sizes are calculated for a wide range of…

Quantum Gases · Physics 2011-12-14 Alexey A. Orel , Paul Dyke , Marion Delehaye , Chris J. Vale , Hui Hu

We have observed the superfluid phase transition in a strongly interacting Fermi gas via high-precision measurements of the local compressibility, density and pressure down to near-zero entropy. Our data completely determine the universal…

Quantum Gases · Physics 2012-02-23 Mark J. H. Ku , Ariel T. Sommer , Lawrence W. Cheuk , Martin W. Zwierlein

Degenerate Fermi gases of atoms near a Feshbach resonance show universal thermodynamic properties, which are here calculated with the geometry of thermodynamics, and the thermodynamic curvature $R$. Unitary thermodynamics is expressed as…

Statistical Mechanics · Physics 2015-06-17 George Ruppeiner

We report on measurements of the critical temperature and the temperature dependence of the condensate fraction for a fermion pair condensate of 6Li atoms. The Bragg spectroscopy is employed to determine the critical temperature and the…

We provide a joint theoretical and experimental investigation of the temperature dependence of the collective oscillations of first sound nature exhibited by a highly elongated harmonically trapped Fermi gas at unitarity, including the…

Ultracold atomic Fermi gases present an opportunity to study strongly interacting Fermi systems in a controlled and uncomplicated setting. The ability to tune attractive interactions has led to the discovery of superfluidity in these…

Quantum Gases · Physics 2010-07-29 J. P. Gaebler , J. T. Stewart , T. E. Drake , D. S. Jin , A. Perali , P. Pieri , G. C. Strinati

Understanding the dynamics of short-range correlations is a central challenge in strongly interacting Fermi gases. In ultracold gases, these correlations are quantified by the contact parameter, yet measurements to date have been limited to…

Fermi gases with magnetically tunable interactions provide a clean and controllable laboratory system for modeling interparticle interactions between fermions in nature. The s-wave scattering length, which is dominant a low temperature, is…

Quantum Gases · Physics 2010-04-05 J. E. Thomas

Theoretical predictions for the dynamic structure factor of a harmonically trapped Fermi superfluid near the BEC-BCS crossover are compared with recent Bragg spectroscopy measurements at large transferred momenta. The calculations are based…

Quantum Gases · Physics 2011-01-06 Peng Zou , Eva D. Kuhnle , Chris J. Vale , Hui Hu

We observe many-body pairing in a two-dimensional gas of ultracold fermionic atoms at temperatures far above the critical temperature for superfluidity. For this, we use spatially resolved radio-frequency spectroscopy to measure pairing…

We report on the measurement of the heat capacity for an optically-trapped, strongly-interacting Fermi gas of atoms. In the experiments, a precise input of energy to the gas is followed by single-parameter thermometry. The thermometry…

Other Condensed Matter · Physics 2007-05-23 J. Kinast , A. Turlapov , J. E. Thomas

We study fermionic pairing in an ultracold two-component gas of $^6$Li atoms by observing an energy gap in the radio-frequency excitation spectra. With control of the two-body interactions via a Feshbach resonance we demonstrate the…

Superconductivity · Physics 2007-05-23 C. Chin , M. Bartenstein A. Altmeyer , S. Riedl , S. Jochim , J. Hecker Denschlag , R. Grimm

Ultracold atomic Fermi gases can be tuned to interact strongly, where they display spectroscopic signatures above the superfluid transition reminiscent of the pseudogap in cuprates. However, the extent of the analogy can be questioned,…

Quantum Gases · Physics 2021-04-21 Yun Long , Feng Xiong , Colin V. Parker

An exotic superfluid phase has been predicted for an ultracold gas of fermionic atoms. This phase requires strong attractive interactions in the gas, or correspondingly atoms with a large, negative s-wave scattering length. Here we report…

Soft Condensed Matter · Physics 2009-11-10 C. A. Regal , D. S. Jin